The invention provides compositions (e.g., pharmaceutical compositions)comprising nucleic acids encoding theserine/threonine kinase PIM-I, and methods for making and using themincluding methods for inducing cellular proliferation, andprotecting cardiac cells from hypoxia and cellular apoptosis. The inventionprovides compositions (e.g., pharmaceutical compositions)comprising nucleic acids encoding PIM-I, and methods for enhancing theregenerative potential of stem cells in the heart.